Phase Formation, Microstructure and Dielectric Properties of Bismuth Potassium Titanate Ceramic Fabricated Using the Combustion Technique

Abstract

The effect of sintering temperature (975–1025°C) on crystal structure, microstructure and dielectric properties of perovskite bismuth potassium titanate (BKT) ceramics was investigated. The pure BKT ceramics were firstly prepared using the combustion technique. The phase purity, crystal structure and microstructure of samples were examined using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The purity phase of BKT samples, which has a tetragonal structure, was observed in all samples. The lattice parameters a, c and the tetragonality tended to decrease with increased sintering temperature. The SEM result showed the average grain size increased (0.37–0.58 μm) with the increase of sintering temperature (975–1025°C). The shrinkage of the ceramics increased when the sintering temperature increased. The maximum density and dielectric constant at Curie temperature were around 5.71 g/cm3 and 3850, and were obtained from the sample sintered at 1020°C for 2 h. Importantly, the preparation using the combustion technique can improve the density and dielectric properties of BKT ceramics.